Prokaryotic picoplankton distribution within the oxygen minimum zone of the central Mexican Pacific across environmental gradients

Authors

  • Zuleima Santana-Vega Universidad Nacional Autónoma de México. Instituto de Ciencias del Mar y Limnología
  • David Uriel Hernández-Becerril
  • Alejandro R. Morales-Blake Universidad de Colima. Facultad de Ciencias Marinas
  • Francisco Varona-Cordero Universidad Nacional Autónoma de México. Instituto de Ciencias del Mar y Limnología
  • Martín Merino-Ibarra Universidad Nacional Autónoma de México. Instituto de Ciencias del Mar y Limnología

DOI:

https://doi.org/10.1590/s1679-87592018004806602

Keywords:

Mexican Pacific, Oxygen minimum zone, Prochlorococcus, Prokaryote picophytoplankton, Synechococcus

Abstract

Marine picophytoplankton has become an important issue to understand the global ecology of phototrophic forms, due to its wide distribution and contribution to biomass and productivity. We studied the abundance, distribution and signature pigments of the prokaryote picophytoplankters Prochlorococcus and Synechococcus during an oceanographic cruise (26 April to 7 May, 2011) in the central Mexican Pacific, a relatively poorlyknown oxygen minimum zone (OMZ), and the effect of three environmental gradients. Prochlorococcus and Synechococcus abundances were comparable with those found in other tropical areas (0.17 to 30.37 X 104 cells mL-1, and 0.9 to 30.97 X 104 cells mL-1, respectively). Prochlorococcus abundances reached highest numbers in deeper waters, often coinciding with the second deep in situ fluorescence (and chlorophyll α) maxima, at oceanic stations, below the nitratecline, whereas Synechococcus abundances were higher at subsurface waters and its concentration maxima usually coincided with the subsurface in situ fluorescence maxima, with slightly higher abundances in coastal stations. Statistical analyses support significantly these results. Distribution of divinyl-chlorophyll α was erratic along the water column and occasionally coincided with the deep in situ fluorescence maxima, whereas the distribution of zeaxanthin usually followed that of chlorophyll α and the abundances of Synechococcus, and peaked together. These results are similar to those previously found in the study area and in more temperate zones, and also to the general trend in OMZ, but confirm that the second deep chlorophyll α maxima are attributed to high Prochlorococcus densities. We additionally found the abundance and distribution of Prochlorococcus and Synechococcus strongly driven by the environmental gradients observed.

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Published

2018-12-21

Issue

Section

Original Article

How to Cite

Prokaryotic picoplankton distribution within the oxygen minimum zone of the central Mexican Pacific across environmental gradients. (2018). Brazilian Journal of Oceanography, 66(2), 157-171. https://doi.org/10.1590/s1679-87592018004806602